DE112005001879B4 - Control device and control method for fluid pressure actuator - Google Patents

Abstract

Fluid pressure actuator control apparatus for controlling an adjustment of a predetermined fluid pressure actuator (5) of at least two fluid pressure actuators (4, 5) to which flows of pressurized fluid discharged from a common fluid pressure source (11) are individually allocated, comprising: an actuator (14) a first detecting means (30) arranged to set an operating state of another fluid pressure actuator (4) among the at least two fluid pressure adjusting drivers (4, 4); 5) and outputting a first detection signal; second detection means (15) arranged to detect an operating state of the common fluid pressure source and output a second detection signal; control origin detection means (20) arranged to detect and the control unit (16) supplying the first and second detection signals from the first and second detection means (30, 15) and configured to control the actuator (14); and set point setting means (17) arranged to set a target displacement for the predetermined fluid pressure actuator (5) in the control device (16); wherein the control device (16) is arranged to set an allotment amount based on the first and second detection signals to calculate the pressurized fluid to the predetermined fluid pressure actuator (5) so that the allocation amount becomes a function of the operating state of the other fluid pressure actuator (4) to control the actuator (14) based on the calculated allocation amount to start the allocation amount in response to the third detection signal from the control origin detection means (20), based on the calculated allocation amount, to determine whether or not the displacement of the predetermined fluid pressure actuator (5) has reached the set target displacement, the actuator (14) based on the result of the En decision to charge it, for each repeated cycle, the first and second detection signals, to calculate the amount of pressurized fluid allotted to the predetermined fluid pressure actuator (5) at each cycle to calculate a cumulative value of the allocation amounts at a plurality of cycles, and controlling the actuator (14) based on the sum value of the calculated allocation amounts.

Description

TECHNICAL AREA

TECHNICAL BACKGROUND

The invention relates to a control device and a control method for controlling the displacement of a fluid pressure actuator, such as a hydraulic cylinder.

In the past, various proposals have been made with respect to a control device which serves to control the displacement of a fluid pressure actuator, such as the length of a hydraulic cylinder, e.g. For example, a bucket leveler has been disclosed in the patent document JP H01-182 419 A described.

In a bucket loader or the like, which includes a boom which is pivoted up and down with respect to the vehicle body by a boom cylinder and a bucket attached to the end portion of the boom and which is tilted by a tilt cylinder, the blade leveler described above is known a blade angle detecting means and a boom angle detecting means provided; and determines from the output signals of the bucket angle detecting means and the boom angle detecting means that the bucket's absolute angle (its angle relative to the earth's surface) has reached an angle which has been set, and returns a bucket operating lever to its neutral position when the bucket's absolute angle the same size as the specified angle. In addition, when the actual absolute angle of the bucket has changed from the predetermined angle due to the rotation of the boom, it calculates a bucket angle compensation signal according to the extent of this change and actuates an electromagnetic valve with this bucket angle compensation signal, thereby supplying pressurized oil to a bucket cylinder so that the specified blade target angle is brought about; and thus, the blade angle is maintained at the predetermined angle by changing its length.

In a wheel loader or the like, during the loading operation, the boom is lowered until it is near the ground, and the bucket is placed horizontally, and the work is performed. Already in the past, there were leveling devices that automatically set the bucket horizontal when the boom was lowered until it is near the ground. However, due to the hardness of the material to be loaded or the like, it may happen that the edge of the airfoil has to be oriented slightly upwards (for example, 5 ° upwards) or downwards. In the past, this operation was performed by the operator who made a fine adjustment. In contrast, with the apparatus of Patent Document 1 described above, it is possible to automatically perform this fine adjustment by preliminarily fixing an angle between the blade and the ground. However, with the structure described above, a boom angle detecting means, a blade angle detecting means, an electromagnetic valve, etc. are provided, and the arrangement is such that the length of the tilting cylinder is controlled while making comparison with the bucket angle previously performed has been set so that the blade angle is always kept constant, regardless of the height position in which the blade is located. As a result, the problems arise that the structure becomes complicated and the costs become high.

From the DE 691 28 708 T2 a hydraulic control system for an earth-moving machine and an associated control method is known, in which the delivery amount of hydraulic pump, which feeds a plurality of hydraulic cylinders as actuators with individually assigned hydraulic substreams, is controlled so that the pump delivery pressure is higher by a predetermined value than the maximum load pressure among the various actuators. The hydraulic quantity of the individual hydraulic partial flows is regulated depending on the operating state of the individual actuators so that it is optimal for each combination of operating states of the individual actuators. For this purpose, control control valves controlling the hydraulic partial flows are stored in advance for all possible operating states including their different combinations of respective differential pressure setpoint values. In this way, the individual hydraulic partial flows are regulated as a function of the other hydraulic partial flows.

From the JP H11-1313532A For example, there is known a hydraulic control for a construction machine in which hydraulic power of a hydraulic pump supplying multiple actuators is divided into two partial flows, one for standard parts of the construction machine and another for auxiliary parts of the construction machine. A hydraulic flow distribution valve controls the division into the two partial flows due to the pump delivery pressure and the Load pressure of the standard parts and that of the additional parts, so that the division is made according to the need. One of the partial flows can be prioritized in advance.

The object of the invention is to provide a fluid pressure actuator with a cost-effective simple structure, which nevertheless allows an exact adjustment of the actuators.

This object is achieved with a device according to claim 1 and a method according to claim 4. Advantageous developments of the invention are the subject of the dependent claims.

In this solution, the arrangement is such that the flow of pressurized fluid is distributed from the common fluid pressure source to the two fluid pressure actuators. As a result, the allocation amount of the pressurized fluid to one of the pressure actuators changes in accordance with the distribution ratio of the pressurized fluid, and this distribution ratio changes according to the operating condition of the other one of the other two-fluid pressure actuators. According to the control system of the invention, the operating state of the other fluid pressure actuator is detected, and the amount of pressurized fluid allocation to the predetermined fluid pressure actuator is calculated based on this detection signal. The calculated allocation amount becomes a function of the operating state of the other fluid pressure actuator, and accordingly changes according to the operation state of the other fluid pressure actuator. The flow of pressurized fluid to the predetermined fluid pressure actuator is controlled based on this type of allocation amount. Accordingly, the displacement of the predetermined fluid pressure actuator is controlled according to the operating state of the other fluid pressure actuator. The structure required for this control is compared with that in the patent document JP H01 -182 419 A described structure of the prior art easier.

list of figures

• 1 Fig. 10 is a linear block diagram showing the overall structure of a control system for controlling the length of a hydraulic cylinder (a so-called tilting cylinder) for tilting a bucket according to an embodiment of the invention;
• 2 Fig. 13 is a side view illustrating the construction of a control origin detecting means of this embodiment;
• 3 are numerical tables and a graph showing a relationship between a blade angle with respect to the ground and a required oil amount for this embodiment, and a relationship between a lift lever operation amount and a distribution coefficient;
• 4 Fig. 10 is a flowchart illustrating a first control method according to this embodiment;
• 5 Fig. 10 is a flowchart illustrating a second control method according to this embodiment; and
• 6 is a numerical table representing a relationship between a blade angle with respect to the ground and a required oil amount for a third control method according to this embodiment.

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the invention will be explained with reference to the drawings.

1 Fig. 10 is a linear block diagram showing, as an example, the overall structure of a control system for controlling the length of a hydraulic cylinder (hereinafter referred to as a tilting cylinder) for tilting a bucket attached to a wheel loader. In 1 is at the end portion of a boom 2 standing on a vehicle body 1 attached is that it can be raised and lowered, a shovel 3 freely rotatably mounted. The vehicle body 1 and the boom 2 are together by a lifting cylinder 4 connected, and the vehicle body and the blade 3 are with each other, via a joint piece 6 and a tilt rod 6T , by a tilting cylinder 5a connected, which is an example of a hydraulic cylinder 5 representing the object of the control.

A hydraulic pump 11 , which is an example of a common fluid pressure source, is powered by a motor 10 driven, and gives an oil pressure flow to a Abführkreis 12 from, and with a throughput, which corresponds to the speed of the motor. The discharge circuit 12 the hydraulic pump 11 is with a flow divider valve 18 connected, and branches into two distribution channels. One of these two branched distribution channels is with a lift valve 13 connected, however, is the other distribution channel with a tilting valve 14a connected, which is an example of an actuator 14 for controlling (for example, allowing or interrupting a flow) the pressure oil flow which is the tilting cylinder 5a is allocated. The lifting valve 13 is with the bottom of the lifting cylinder 4 through a bottom feed channel 41 connected, however, it is with the head side of the lifting cylinder 4 through a head-side feed channel 42 connected. The tilt valve 14a is with the bottom of the tilt cylinder 5a through a bottom feed channel 51 connected, however, it is with the head side of the tilt cylinder 5a through a head-side feed channel 52 connected.

The lifting valve 13 drives the lifting cylinder 4 characterized in that there is pressure oil to the bottom of the lifting cylinder 4 sends and drives the lifting cylinder 4 by sending pressurized oil to its head. The tilt valve 14a drives the tipping cylinder 5a by taking pressure oil to the bottom of the tilt cylinder 5a sends, and drives the tilt cylinder 5a by sending pressurized oil to its head. In this way, each of the valves performs extension and retraction and controls the maintenance of the length of its associated cylinder 4 . 5a ,

At the engine 10 is an engine speed sensor 15a which is an example of a discharge flow rate detecting means 15 which illustrates the discharge flow rate as an example of the operating state of the hydraulic pump 11 detected; and at the dump detection device 5a is a control origin point detecting means 20 provided, which detects the fact that the length of the tilt cylinder 5 has become equal to a reference length corresponding to a predetermined control origin point. With a control device 16 are the engine speed sensor 15a , the control origin detection device 20 and a setpoint adjustment device 17 connected to a setpoint for the length of the tilt cylinder 5a sets. This Soilwert-adjustment 17 For example, it may be a rotary switch, a digital switch, a button switch, or the like. In the control device 16 a programmed computer, a hardwired circuit for a dedicated dedicated function, or a programmable hardwired circuit is used; or a combination of these may be used.

On a rocker arm 31a , which is an example of a control start instruction device 31 is, which instructs the beginning of a cylinder length control, a detent position is provided, as shown by the broken lines in the figure; and the arrangement is such that the beginning of the control is instructed by this detent position. If the driver this toggle 31a towards the rear (from the position shown on the right in the figure) to the end of its stroke, then the arrangement is such that the rocker arm 31a is held in its rest position. There is also a latch release device 31a on the rocker arm 31a and upon receipt of a release instruction signal from the control device 16 this releases the detent and moves the lever back to its retained position.

The lifting valve 13 , the lifting lever 30 Pressing this, the tilt valve 14a and the rocker arm 31a that operates this are, for example, of the electric type, and each of them is with the control device 16 connected. The arrangement is such that the lifting lever 30 the control device 16 provides a signal indicative of the amount of operation (for example, in percent) of the lift lever 30 indicating this signal is an example of a signal indicating the operating state of the lifting cylinder 4 shows.

When the driver leverages 30 pushes forward (ie, it moves from its neutral position shown in the figure to the left), then a signal from the lifting lever 30 to the control device 16 sent, and the lifting valve 13 is by a signal from the control device 16 controlled, and by pressurized oil, to the top of the lifting cylinder 4 is sent, the lifting cylinder 4 retracted, and the boom 2 is rotated down so that the boom 2 is moved downwards. In addition, when the driver raises the lever 30 pulls it backwards (ie moves it to the right from its position shown in the figure), then a signal from the lifting lever 30 to the control device 16 sent, and the lifting valve 13 is by a signal from the control device 16 operated, and by pressurized oil, to the bottom side of the lifting cylinder 4 is sent, the cylinder becomes 4 extended, and the boom 2 is rotated upwards so that the boom 2 is raised.

When the driver releases the rocker arm 31 pushes forward (ie, it moves from its neutral position shown in the figure by solid lines to the left), then a signal from the rocker arm 31a to the control device 16 sent, and the tilt valve 14a is by a signal from the control device 16 controlled, and by pressure oil, to the head of the tilt cylinder 5a is sent, the tilting cylinder 5a retracted, and over the joint piece 6 and the tilt rod 6T becomes the scoop 3 rotated downwards. In addition, when the driver turns the rocker arm 31a pulls backwards (i.e., moves it from its position shown by solid lines in the figure to the right), then a signal from the rocker arm 31a to the control device 16 sent, and the tilt valve 14a is by a signal from the control device 16 so pressed that, by pressurized oil, to the bottom of the tilt cylinder 5a is sent, the tilting cylinder 5a is extended, and over the joint piece 6 and the tilt rod 6T the shovel 3 is rotated upwards.

2 Fig. 12 is an explanatory figure showing the structure of the control origin detecting means 20 represents. In 2 is a proximity switch 22 near the head of the cylinder tube 21 of the tilt cylinder 5a intended. A detection element 24 is with the cylinder rod 23 connected. When the tilt cylinder 5a reaches a fixed length, the end portion passes 24T of the detection element 24 to a position that the proximity switch 22 overlaps, and the proximity switch 22 works and generates a signal.

When the driver releases the rocker arm 31a pulls back and the rocker arm 31a is held in its rest position, then a signal instructing the beginning of a cylinder length control, from the rocker arm 31a to the control device 16 sent, and the tilt valve 14a is by a signal from the control device 16 controlled, and by pressure oil, to the bottom side of the tilt cylinder 5a is sent, the tilting cylinder 5a extended. And it will, if as previously described the tipping cylinder 5a its set length reaches the signal from the proximity switch 22 to the control device 16 Posted.

Next, the operation will be explained. In 1 takes place during extension of the lifting cylinder 4 a raising of the boom, and when retracting a lowering of this. The shovel 3 is when extending the tilt cylinder 5a rotated upward and tilted back, and when it retracts upward rotated and emptied. When the wheel bearing performs excavation, a digging operation is performed by extending the lift cylinder 4 and lifting the boom 2 , and by retracting the tilt cylinder 5a and emptying the shovel 3 Normally, when the driver finishes a digging operation, he next brings the wheel loader quickly to a loading position during the lifting cylinder 4 is retracted and the boom 2 it is lowered, he an extension of the tilting cylinder 5a through and causes the scoop 3 is tilted back.

During normal loading work, the end section of the boom becomes 2 lowered until it is near the bottom, and the bottom surface 3T the shovel 3 is placed horizontally. However, it is sometimes the case that due to the hardness of the material constituting the object of loading or the like, the end portion of the blade 3 is adjusted so that it is slightly inclined upwards (for example + 5 °) or slightly inclined downwards (for example -5 °). In other words, sometimes it happens that the angle α of the floor surface 3T the shovel 3 with respect to the ground between -5 ° and + 5 °. The angle α of the floor surface 3T the shovel 3 with respect to the ground is determined by the length of the tilt cylinder 5a determines when the boom 2 is in the state of charge (the state in which the end portion of the boom has been lowered to a low position near the earth's surface, as in FIG 1 shown). Accordingly, it is possible to adjust the angle α of the bottom surface 3T the shovel 3 with respect to the ground by controlling the length of the tilting cylinder 5a to control. Accordingly, the above-described target value setting direction 17 a desired value of the angle α of the ground surface 3T the shovel 3 with respect to the ground, instead of the length of the tilting cylinder 5a establish.

Hereinafter, a cylinder length control method explained by the in 1 shown cylinder length control device is performed. 3 (a) is an example of a numerical table 1 which shows the relationship between the angle α of the ground surface 3T the shovel 3 with respect to the soil and the required Ӧlmenge Vh for the tilt cylinder 4 represents. In this embodiment, during excavation, the arrangement is such that it is possible to control the angle α of the ground surface 3T the shovel 3 with respect to the ground to any desired angle in the range of -5 ° to + 5 °, which is a section near 0 ° within the entire possible range for this angle α with respect to the ground. This numerical table 1 is a table that is generated by placing the boom 2 takes in the state of charge, the point at which the angle α of the bottom surface 3T the shovel 3 with respect to the ground is equal to -5 °, as the control origin takes, and the length L1 of the tilt cylinder 5a at this point as a reference, and you take the length L2 (= the desired length LM) of the tilt cylinder 5a gets to the bottom surface 3T the shovel 3 to bring to a predetermined angle with respect to the ground, and the required amount of oil Vh is calculated, which is the amount of oil that is needed, so that its length depends on the length L1 on the length L2 is changed. In other words, this numerical table 1 shows when the required amount of oil for the tilt cylinder 5a is taken as zero at the control origin point that for each angle with respect to the ground α, the required amount of oil Vh (for example in cc) of the bottom side of the tilt cylinder 5a must be supplied to the bottom surface 3T the shovel 3 to tilt on the angle α (in °) with respect to the ground to the plus side. The numerical values in this numerical table 1 are preliminarily set in the control device 16 saved.

The engine speed is based on the signal from the engine speed sensor 15a receive. As described above, the hydraulic fluid coming from the hydraulic pump 11 is dispensed, split and the lifting valve 13 and the tilt valve 14a fed. Accordingly, when during the cylinder length control operation, the lift cylinder flows 4 Pressure oil is supplied, a share of that of the hydraulic pump 11 delivered throughput in the lifting cylinder 4 a, and there is a reduction in the hydraulic flow rate, the tilting cylinder 5a is supplied.

This is due to obtain the amount of oil that the tilt cylinder 5 is fed when the lifting cylinder described above 4 is controlled, a numerical table 2 set up, which shows the relationship between the operation amount of the lifting lever 30 and the amount of hydraulic fluid to the tilt cylinder 5a is assigned, as distribution coefficient shows, as in 3 (b) shown. The numerical values in this numerical table 2 are preliminarily set in the control device 16 saved. The upper line in the numerical table 2 is the operation amount of the lift lever 30 (for example, in%), however, the bottom line is the distribution coefficient. This distribution coefficient indicates the proportion of the amount of oil that is the tilting cylinder 5a is allocated, with respect to the delivered flow rate of pressure oil from the hydraulic pump 11 , The relationship between the distribution coefficient that the control device 16 based on this numerical table 2, and the operation amount of the lift lever 30 is exemplary in 3 (c) shown. At the in 3 (c) illustrated example, between depressing operation amounts of the lifting lever 30 from 0% to 90%, the distribution coefficient is a linear function of the push-down operation amount of the lift lever 30 and the distribution coefficient decreases more as the depressing operation amount increases (in other words, the more the supply amount of pressurized oil to the elevating cylinder) 4 increases). For depression actuation levels of 90% to 100%, the distribution coefficient has the value 1 as a free lowering of the boom 2 is reached.

The tipping cylinder 5a allocated amount of oil Vt is obtained by the following equation 1: $$\begin{array}{l}\text{Allocated amount of oil}\left(\text{Vt}\right)=\text{Hydraulikpumpenkapazitat}\left(\text{cc / rev}\right)\times \text{Engine speed}\left(\text{revolutions}\right)\\ \times \text{Partition coefficient}\end{array}$$

Hereinafter, a first cylinder length control method for controlling the angle of the blade 3 with respect to the soil to their specified value, after completion of the excavation until the beginning of the loading, with reference to the flow chart of 4 and the table of 3 explained.

a) In the case of 4 illustrated step 101 the driver determines a target angle αM of the blade 3 with respect to the ground (or a desired length LM for the tilting cylinder 5a , and gives them to the controller 16 via a setpoint adjustment device 17 one.

b) At step 102 the driver operates the control start instruction device 31 in other words he sets the rocker arm 31a in its rest position and has the control device 16 to start with the cylinder length control. Normally, this instruction is issued right after the excavation is finished, when lowering the boom 2 and a tip back of the bucket 3 be executed. Accordingly, at this time, the bucket tilt valve is transmitting 14a Pressure oil to the bottom side of the tilt cylinder 5a so that the tilt cylinder 5a extending.

c) At step 103 calculates the control device 16 the required amount of oil Vh from the numerical table 1 based on the input target angle αM with respect to the ground. If the target angle with respect to the ground αM is, for example, 4 °, then the required quantity of oil Vh, which corresponds to this target angle with respect to the ground αM, ie an angle with respect to the ground of α = 4 °, is found to be 3150 ,

d) At step 104 becomes the control device 16 the detection signal from the control origin detecting means 20 supplied, and the control device determines whether the length of the tilt cylinder 5a at the control origin point (corresponding to an angle α with respect to the ground of -5 °) has arrived. If YES, the control flow goes on to step 105 however, in the case of NO, the control flow goes to step 104 back. In other words, when the tilt cylinder 5a reaches its specified length, which is to become the control origin point, the signal from the proximity switch 22 to the control device 16 sent, and the control flow continues to step 105 , Usually happens while the shovel 3 is tilted back after completion of the excavation (ie during extension of the tilt cylinder), the length of the tilt cylinder 5a at any time inevitably the control origin, and the control flow goes on to step 105 ,

e) At step 105 becomes the control device 16 the detection signal from the engine speed sensor 15a and the operation amount signal from the lift lever 30 supplied, and the control device calculates the sum value of the oil amount Vt, the tilting cylinder 5a from the hydraulic pump 11 The sum value of the allocated oil amount Vt which is calculated is a function of the engine speed, and accordingly, their sum value also changes as the engine speed changes. In addition, this sum value is a function of the amount of operation of the lift lever 30 , and is accordingly calculated by the change in the amount of operation of the lift lever 30 is taken into account. In other words, at step 105A the detection signal from the engine speed sensor 15a and based on this detection signal, the engine speed is detected during a single cycle of predetermined time duration (for example, 0.01 second). At step 105B the operation amount signal becomes from the lift lever 30 fed, and at step 105C From this operation amount signal and the numerical table 2, a distribution coefficient is determined which corresponds to the current depression operation amount of the lift lever 30 equivalent. And at step 105D is the amount of oil Vt, the tilting cylinder 5a in a single cycle is calculated according to equation 1 based on the engine speed of the distribution coefficient. This amount of oil Vt, which is calculated in a single cycle, which is calculated, is not only a function of the engine speed, but also a function of the operating amount of the shift lever 30 , Accordingly, this allocated amount of oil Vt not only changes as the engine speed changes, but also changes as the operation amount of the lift lever increases 30 changes. And at step 105E For example, the amount of oil Vt allocated in the current cycle is added to the sum value of the allocated amount of oil Vt calculated until the previous cycle.

This type of step 105 is repeated at each cycle of predetermined time duration (for example, 0.01 second), and the allocated oil amount Vt calculated for each cycle is accumulated. In other words, the hydraulic fluid discharge amount Vt, which is the tilting cylinder, is calculated 5a during a single cycle (0.01 second), and to this allocated amount of oil Vt is added the amount of oil Vt which is the tilting cylinder 5a during the next cycle (0.01 second), and this is repeated. The sum value of the assigned oil amount Vt calculated in this way denotes the total amount of oil that is the tilting cylinder 5a during the period from the time when the length of the tilt cylinder 5a arrived at the control origin point until the current time has been allocated. It will be understood that in order to accurately calculate this allocated amount of oil Vt, the aim is to calculate the amount of oil allocated in a shortest possible interval; it is acceptable to perform this calculation every predetermined time interval appropriately set between 0.1 seconds to 0.005 seconds.

f) At step 106 compares the control device 16 the sum value of the allocated oil amount Vt and the required oil amount Vh, and decides whether or not the sum value of the allocated oil amount Vt has arrived at the required oil amount Vh. If the result is YES, then the control flow goes on to step 107 on the other hand, if the result is NO, the control flow goes on to step 105 of the next cycle.

g) At step 107 gives the control device 16 a stop signal to the tilt valve 14a and she closes the dump valve 14a and puts the tilting cylinder 5a in the holding state (the stationary state). In addition, it simultaneously gives a release signal to the rocker arm 31a and releases its detent, and clears the control start command.

1. A) Wie in 5 dargestellt, bestimmt bei Schritt 201 der Fahrer einen Sollwinkel αM der Schaufel 3 bezüglich des Erdbodens (oder eine Soll-Länge LM für den Kippzylinder 5a), und gibt diesen mittels einer Sollwert-Einstelleinrichtung 17 in die Steuervorrichtung 16 ein.
2. B) Bei Schritt 202 betätigt der Fahrer die Steuerungsbeginn-Anweisungsvorrichtung 31, mit anderen Worten stellt er den Kipphebel 31a in dessen Rastposition und weist die Steuervorrichtung 16 an, mit der Zylinderlängensteuerung zu beginnen. Wie zuvor beschrieben sendet normalerweise zu diesem Zeitpunkt das Kippventil 14a Drucköl an die Bodenseite des Kippzylinders 5a, so dass der Kippzylinder 5a ausfährt.
3. C) Bei Schritt 203 berechnet die Steuervorrichtung 16 die erforderliche Ölmenge Vh aus der numerischen Tabelle 1 basierend auf dem eingegebenen Sollwinkel αM bezüglich des Erdbodens
4. D) Bei Schritt 204 wird der Steuervorrichtung 16 das Motordrehzahlsignal zugeführt, und sie erhält die Motordrehzahl N (Umdrehungen/Sekunde) (bei Schritt 204A). Außerdem wird der Steuervorrichtung 16 das Betätigungsausmaßsignal vom Anhebehebel 30 zugeführt (bei Schritt 204B), und sie bestimmt einen Verteilungskoeffizienten, der dem aktuellen Herunterdrück-Betätigungsausmaß des Anhebehebels 30 entspricht, aus der numerischen Tabelle 2 (bei Schritt 204C). Und, unter Verwendung der Motordrehzahl N (Umdrehungen/Sekunde) und des Verteilungskoeffizienten, berechnet die Steuervorrichtung 16 (bei Schritt 204D) die Ölmenge VtJ, die dem Kippzylinder 5a pro Zeiteinheit zugeteilt wird. Diese pro Zeiteinheit zugeteilte Ölmenge VtJ, die berechnet wird, ist nicht nur eine Funktion der Motordrehzahl, sondern auch eine Funktion des Betätigungsausmaßes des Anhebehebels 30. Außerdem teilt die Steuervorrichtung 16 die benötigte Ölmenge Vh durch die pro Zeiteinheit zugeteilte Ölmenge VtJ, und berechnet (in Schritt 204E) die Zeitdauer Th (= Vh/VtJ), die benötigt wird, bis die gesamte dem Kippzylinder 5a zugeteilte Ölmenge die benötigte Ölmenge Vh erreicht. Es wird darauf verwiesen, dass diese pro Zeiteinheit zugeteilte Ölmenge VtJ durch die folgende Gleichung 2 erhalten wird. $$\text{VtJ}=\text{Hydraulikpumpenkapazitat }\left(\text{cc/Umdrehung}\right)\times \text{N }\left(\text{Umdrehungen/Sekunde}\right)\times \text{Verteilungskoeffizient}$$
   
5. E) Bei Schritt 205 wird der Steuervorrichtung 16 das Erfassungssignal von der Steuerungsursprungspunkt-Erfassungseinrichtung 20 zugeführt, und die Steuervorrichtung bestimmt, ob die Länge des Kippzylinders 5a am Steuerungsursprungspunkt angekommen ist, oder nicht. Falls JA, d. h. wenn die Länge des Kippzylinders 5a am Steuerungsursprungspunkt angekommen ist, dann geht der Steuerungsablauf weiter auf Schritt 206, hingegen geht im Fall von NEIN, d. h. wenn die Länge des Kippzylinders 5a nicht beim Steuerungsursprungspunkt angekommen ist, dann der Steuerungsablauf zurück vor Schritt 205.
6. F) Bei Schritt 206 entscheidet die Steuervorrichtung 16, ob seit dem Zeitpunkt, bei dem die Länge des Kippzylinders 5a beim Steuerungsursprungspunkt angekommen ist, die erforderliche Zeitdauer verstrichen ist, oder nicht. Falls JA, geht der Steuerungsablauf weiter auf Schritt 207, hingegen geht im Fall von NEIN der Steuerungsablauf zurück vor Schritt 206.
7. G) Bei Schritt 207 gibt die Steuervorrichtung 16 ein Stoppsignal an das Kippventil 14a aus, und sie schließt das Kippventil 14a und versetzt den Kippzylinder 5a in den Haltezustand (den stationaren Zustand). Außerdem gibt sie gleichzeitig ein Lösesignal an den Kipphebel 31a aus und löst dessen Rastung, und sie löscht den Steuerungsbeginnbefehl.

Next, a second cylinder length control method for controlling the angle of the blade 3 with respect to the soil to their specified value, after completion of the excavation to the beginning of the loading, with reference to the flow chart of 5 explained. This second control method is suitable to be carried out when the operation amount of the lift lever 30 does not change much (for example, if it is in the range of 90% to 100%, as shown in 3 (c) ).

1. A) As in 5 represented, determined at step 201 the driver a target angle αM of the blade 3 with respect to the ground (or a desired length LM for the tilting cylinder 5a ), and outputs this by means of a setpoint adjuster 17 into the control device 16 one.
2. B) At step 202 the driver operates the control start instruction device 31 in other words he sets the rocker arm 31a in its rest position and has the control device 16 to start with the cylinder length control. As previously described, the tilt valve normally sends at this time 14a Pressure oil to the bottom side of the tilt cylinder 5a so that the tilt cylinder 5a extending.
3. C) At step 203 calculates the control device 16 the required amount of oil Vh from the numerical table 1 based on the input target angle αM with respect to the ground
4. D) At step 204 becomes the control device 16 the engine speed signal is supplied, and it receives the engine speed N (revolutions / second) (in step 204A ). In addition, the control device 16 the operation amount signal from the lift lever 30 supplied (at step 204B ), and it determines a distribution coefficient corresponding to the current depression operation amount of the lift lever 30 from the numeric table 2 (at step 204C ). And, using the engine speed N (revolutions / second) and the distribution coefficient, the controller calculates 16 (at step 204D ) the amount of oil VtJ that the tilting cylinder 5a allocated per unit time. This amount of oil VtJ, which is calculated per unit time, which is calculated, is not only a function of the engine speed, but also a function of the amount of operation of the lift lever 30 , In addition, the control device shares 16 the required amount of oil Vh by the amount of oil VtJ allocated per unit time and calculated (in step 204E ) the time Th (= Vh / VtJ) that is needed until the whole of the tilt cylinder 5a allocated amount of oil reaches the required amount of oil Vh. It is to be noted that this oil amount VtJ allocated per unit time is obtained by the following equation 2. $$\text{VTJ}=\text{Hydraulikpumpenkapazitat}\left(\text{cc / rev}\right)\times \text{N}\left(\text{Revolutions / second}\right)\times \text{Partition coefficient}$$
   
5. E) At step 205 becomes the control device 16 the detection signal from the control origin detecting means 20 supplied, and the control device determines whether the length of the tilt cylinder 5a arrived at the control origin point or not. If YES, ie if the length of the tilt cylinder 5a has arrived at the control origin, then the control flow goes on to step 206 however, in the case of NO, ie if the length of the tilt cylinder 5a not arrived at the control origin point, then the control flow back before step 205 ,
6. F) At step 206 the controller decides 16 whether from the date when the length of the tilt cylinder 5a arrived at the control origin point, the required period of time has elapsed or not. If YES, the control flow goes on to step 207 on the other hand, in the case of NO, the control flow goes back to step 206 ,
7. G) At step 207 gives the control device 16 a stop signal to the tilt valve 14a and she closes the dump valve 14a and puts the tilting cylinder 5a in the holding state (the stationary state). In addition, it simultaneously gives a release signal to the rocker arm 31a and releases its detent, and clears the control start command.

Next, a third cylinder length control method for controlling the angle of the blade 3 with regard to the soil at their specified value. 6 is a numerical table 3 exemplifying a relationship between the angle α of the ground surface 3T the shovel 3 with respect to the ground and the required amount of oil Vh for the tilting cylinder 4 shows. Also in this example, during digging operations (during the state of charge), the arrangement is such that the angle α of the ground surface 3T the shovel 3 with respect to the ground between -5 ° and + 5 °. The numerical table 3 is a numerical table in which, when the boom 2 is in the state of charge, one takes as control origin the point at which the angle α of the ground surface 3T the shovel 3 with respect to the ground level is 0 ° (in other words, the point at which the ground surface 3T the shovel 3 parallel to the surface of the ground), and the length L01 of the tilt cylinder 5a at this point takes as a reference, and a length L02 (a target length LM) for the tilt cylinder 5a to the bottom surface 3T the shovel 3 to obtain a specified angle with respect to the soil, and a required amount of oil Vh, which is the required amount of oil, is obtained by the length thereof L01 on the length L02 to bring is calculated.

In other words, if supplies for the tilt cylinder 5a required amount of oil at the control origin assumes as zero, the numerical table 3 for each angle α of the ground surface 3T the blade with respect to the ground, the required amount of oil Vh (for example, in cc), the bottom side of the tilt cylinder 5a must be assigned to the angle α (in °) of the floor area 3T the shovel 3 tilt to the plus side; and it also provides the required amount of oil Vh (for example, in cc) for each angle α with respect to the ground, that of the top of the tilt cylinder 5a must be supplied to the angle α (in °) of the ground surface 3T the shovel 3 tilt to the minus side. The numerical values in this numerical table 3 are preliminarily set in the control device 16 saved.

In this manner, when the control origin is set to 0 °, which is the midpoint of the possible range -5 ° to + 5 ° of the angle α with respect to the ground, compared with the case where the control origin is set to -5 ° was, ie to the one end of the possible range of -5 ° to + 5 ° of the angle α with respect to the ground as in the exemplary In 3 (a) shown numerical table 1, the accuracy of the determination improves whether the total amount of the allocated amount of supplied oil has arrived at the required amount of oil Vh. However, in this method, there is a problem that when the blade 3 after the excavation is tipped back, it is absolutely necessary to tilt the cylinder 5a temporarily return to the length corresponding to the control origin 0 °.

This control method can be performed with a routine that is substantially the same as that in the flowchart of FIG 4 is shown routine. In this case, only the details of the control differ from step 103 until step 105 those of the first control method which have already been explained. Calculated in detail at step 103 the control device 16 the required amount of oil Vh from the numerical table 3, based on the target angle αM with respect to the ground If, for example, the target angle αM with respect to the ground + 4 °, then the required amount of oil Vh to 1400, whereas the target angle αM with respect to the ground -4 °, then the required amount of oil Vh becomes 700. Since the pressure oil when the target angle αM with respect to the ground is on the plus side, to the bottom side of the tilt cylinder 5a Accordingly, the amount of oil required is larger as compared with the case where the pressure oil is sent to the head side. This is due to the fact that the volume of the head side space of the cylinder is less than the volume on the bottom side space, just by the volume of the rod, which is inserted into this.

And at step 104 becomes the control device 16 the detection signal from the control origin detecting means 20 supplied, and the control device makes a decision as to whether the length of the tilt cylinder 5a at the control origin (which corresponds to an angle α with respect to the ground of zero) or not. If NO, if the length of the tilt cylinder 5 has not arrived at the control origin point, the control flow goes back to step 104 , If YES, if the length of the tilt cylinder 5a has arrived at the control origin, takes place, together with a progression of the control flow to step 105 if the target angle αM is on the positive side with respect to the ground, by the control device 16 sending a control signal to the tilt valve 14a , so that the pressure oil to the bottom side of the tilt cylinder 5a is sent, and the controller exerts a control of the tilting cylinder 5a extend, however, sends, if the target angle αM with respect to the ground on the minus side, the control device 16 a control signal to the tilt valve 14a , so that the pressure oil to the top of the tilt cylinder 5a is sent, and exercises a control, so that the tilt cylinder 5a is retracted. The details of the control in the remaining steps are the same as those of the first control method, and these have already been described with reference to FIG 4 explained.

Otherwise, this third control method can also with the in the flowchart of 5 shown routine. In this case, only the details of the control differ from step 203 until step 206 those of the second control method which have already been explained. That is, at step 203 calculates the control device 16 the required amount of oil Vh from the numerical table 3, based on the target angle αM with respect to the ground.

And at step 205 becomes the control device 16 the detection signal from the control origin detecting means 20 supplied, and the control device makes a decision as to whether the length of the tilt cylinder 5a at the control origin (which corresponds to an angle α with respect to the ground of zero) or not. If NO, if the length of the tilt cylinder 5 has not arrived at the control origin point, the control flow goes back to step 205 , If YES, if the length of the tilt cylinder 5a At the control origin point, the control flow goes on to step 206 and when the target angle αM is on the plus side with respect to the ground, the controller sends 16 a control signal to the tilt valve 14a , so that the pressure oil to the bottom side of the tilt cylinder 5a is sent, and exercises a control, so that the tilt cylinder 5a is extended, however, sends, if the target angle αM with respect to the ground on the minus side, the control device 16 a control signal to the tilt valve 14a , so that the pressure oil to the top of the tilt cylinder 5a is sent, and exercises a control, so that the tilt cylinder 5a is retracted. The details of the control in the past steps are the same as those of the second control method, and these have already been described with reference to FIG 5 explained.

According to the above-described embodiments of the invention, by instructing the control device to start longitudinal control of the hydraulic cylinder and inputting a target length for the hydraulic cylinder, it is possible to automatically control the length of the hydraulic cylinder to the target length , Because of this, by setting the length for the tilting cylinder used for tilting the bucket, for example, by a wheel loader during loading work, it is possible to automatically control the tilting angle of the bucket to a target value. Accordingly, it is possible to appropriately select the angle between the bucket and the ground according to the material to be loaded, thereby automatically controlling the bucket easily to a desired angle with respect to the ground, so that it is possible to control the bucket Improve driver's work performance and work efficiency. In addition, the hardware structure of the cylinder length control system according to these embodiments is a comparatively simple structure in which only the two sensors are added to an already existing hydraulic system, namely, the discharge amount detecting means for the hydraulic pump and the cylinder position detecting means, and the control means and the target value Adjusting device, so that the costs are low.

Although examples of application to a wheel loader have been described for the embodiments described above, this is for illustration purposes only and does not mean that the scope of the invention is limited only to this application. The invention can be applied to automatic control of the displacement of a hydraulic cylinder, or any other fluid pressure actuator in hydraulic machines of various types, such as a hydraulic excavator or a hydraulic crane or the like.

Claims (4)

Fluid pressure actuator control apparatus for controlling an adjustment of a predetermined fluid pressure actuator (5) of at least two fluid pressure actuators (4, 5) to which flows of pressurized fluid discharged from a common fluid pressure source (11) are individually allocated, comprising: an actuator (14) adapted to control a flow of the pressurized fluid that is allocated to the predetermined fluid pressure actuator (5); a first detection means (30) arranged to detect an operation state of another fluid pressure actuator (4) from the at least two fluid pressure actuators (4, 5) and to output a first detection signal; second detection means (15) arranged to detect an operating state of the common fluid pressure source and to output a second detection signal; a control origin point detecting means (20) arranged to detect that the displacement of the predetermined fluid pressure actuator (5) has reached a predetermined control origin point and to output a third detection signal; a control device (16) to which the first and second detection signals are supplied from the first and second detection means (30, 15) and which is arranged to control the operation device (14); and set point setting means (17) arranged to set a target displacement for the predetermined fluid pressure actuator (5) in the control device (16); wherein the control device (16) is arranged to calculate, based on the first and second detection signals, an allocation amount of pressurized fluid to the predetermined fluid pressure actuator (5) so that the allocation amount becomes a function of the operating state of the other fluid pressure actuator (4) To control the actuator (14) based on the calculated allotment amount, to start calculating the allotment amount in response to the third detection signal from the control origin detecting means (20), to determine whether the adjustment of the predetermined fluid pressure actuator (5) is based on the calculated allotment amount the setpoint adjustment has arrived or not, to control the actuator (14) based on the result of the decision that it is supplied for each repeated cycle, the first and the second detection signal to calculate the allocation amount of pressurized fluid, which is allocated to the predetermined fluid pressure actuator (5) in each cycle to calculate a sum value of the allocation amounts calculated at a plurality of cycles, and to control the actuator (14) based on the sum value of the calculated allocation amounts. Fluid pressure actuator control device according to Claim 1 in which the desired displacement can be set as desired within a predetermined displacement range; and wherein the control origin is set to a predetermined displacement within the predetermined displacement range. Fluid pressure actuator control device according to Claim 1 in that the control device (16) is supplied with the first and second detection signals at a certain time, the control device calculates the pressurized fluid allocation amount allocated to the predetermined fluid pressure actuator per unit time, and a time period for controlling the flow of the pressurized fluid the predetermined fluid pressure actuator is calculated based on the calculated allocation amount per unit time, and controls the actuator (14) based on the calculated time period. A fluid pressure actuator control method for controlling an adjustment of a predetermined fluid pressure actuator (5) of at least two fluid pressure actuators (4, 5) to which flows of pressurized fluid discharged from a common fluid pressure source (11) are individually assigned, comprising: Controlling a flow of the pressurized fluid, which is allocated to the predetermined fluid pressure actuator (5), by means of an actuator (14); Detecting an operating condition of another fluid pressure actuator (4) from the at least two fluid pressure actuators and outputting a first detection signal; Detecting an operating condition of the common fluid pressure source (11) and outputting a second detection signal; Detecting that the adjustment of the predetermined fluid pressure actuator has arrived at a predetermined control origin point, and outputting a third detection signal; Supplying the first and second detection signals to a controller (16) which controls the actuator (14); Setting a desired displacement for the predetermined fluid pressure actuator (5); Calculating an allocation amount of pressurized fluid to the predetermined fluid pressure actuator (5) based on the first and second detection signals by the control device (16) so that the allocation amount becomes a function of the operating state of the other fluid pressure actuator (4); Begin to calculate the allocation amount in response to the third detection signal from the control origin detecting means (20); Determining, based on the calculated allocation amount, whether or not the displacement of the predetermined fluid pressure actuator (5) has reached the set target displacement; Calculating the allocation amount of pressurized fluid corresponding to the predetermined one Fluid pressure actuator (5) is allocated each cycle; Calculating a sum value of the allocation amounts calculated at a plurality of cycles; Controlling the actuator (14) based on the calculated allocation amount; Controlling the actuator (14) based on the result of the decision; Controlling the actuator (14) based on the sum value of the calculated allocation amounts.

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